The federal judge overseeing litigation between the city and workers at ground zero on Friday rejected a settlement reached by the two sides, telling lawyers that it did not provide enough compensation to plaintiffs and needed to be renegotiated under his supervision.

The decision by Judge Alvin K. Hellerstein, in a hearing in United States District Court in Manhattan, came only a week after the settlement was announced after six years of legal maneuvering. It provided for payouts of $575 million to $657.5 million in cases filed by some 10,000 rescue and cleanup workers who say they suffered health damages from toiling at ground zero after the 2001 terrorist attack.

"This is no ego trip for me,” Judge Hellerstein told a packed but hushed courtroom moments after hearing emotional testimony from some of the plaintiffs. "This is work. I will preside over a process that’s fair.”